/**
 *               ~ CLNDR v1.5.1 ~
 * ==============================================
 *       https://github.com/kylestetz/CLNDR
 * ==============================================
 *  Created by kyle stetz (github.com/kylestetz)
 *       & available under the MIT license
 * http://opensource.org/licenses/mit-license.php
 * ==============================================
 *
 * This is the fully-commented development version of CLNDR.
 * For the production version, check out clndr.min.js
 * at https://github.com/kylestetz/CLNDR
 *
 * This work is based on the
 * jQuery lightweight plugin boilerplate
 * Original author: @ajpiano
 * Further changes, comments: @addyosmani
 * Licensed under the MIT license
 */
 (function (factory) {
    // Multiple loading methods are supported depending on
    // what is available globally. While moment is loaded
    // here, the instance can be passed in at config time.
    if (typeof define === 'function' && define.amd) {
      // AMD. Register as an anonymous module.
      define(['jquery', 'moment'], factory);
    } else if (typeof exports === 'object') {
      // Node/CommonJS
      factory(require('jquery'), require('moment'));
    } else {
      // Browser globals
      factory(jQuery, moment);
    }
  }(function ($, moment) {
    // Namespace
    var pluginName = 'clndr';
  
    // This is the default calendar template. This can be overridden.
    var clndrTemplate =
      "<div class='clndr-controls'>" +
          "<div class='clndr-control-button'>" +
              "<span class='clndr-previous-button'>previous</span>" +
          '</div>' +
          "<div class='month'><%= month %> <%= year %></div>" +
          "<div class='clndr-control-button rightalign'>" +
              "<span class='clndr-next-button'>next</span>" +
          '</div>' +
      '</div>' +
      "<table class='clndr-table' border='0' cellspacing='0' cellpadding='0'>" +
          '<thead>' +
              "<tr class='header-days'>" +
              '<% for(var i = 0; i < daysOfTheWeek.length; i++) { %>' +
                  "<td class='header-day'><%= daysOfTheWeek[i] %></td>" +
              '<% } %>' +
              '</tr>' +
          '</thead>' +
          '<tbody>' +
          '<% for(var i = 0; i < numberOfRows; i++){ %>' +
              '<tr>' +
              '<% for(var j = 0; j < 7; j++){ %>' +
              '<% var d = j + i * 7; %>' +
                  "<td class='<%= days[d].classes %>'>" +
                      "<div class='day-contents'><%= days[d].day %></div>" +
                  '</td>' +
              '<% } %>' +
              '</tr>' +
          '<% } %>' +
          '</tbody>' +
      '</table>';
  
    // Defaults used throughout the application, see docs.
    var defaults = {
      events: [],
      ready: null,
      extras: null,
      render: null,
      moment: null,
      weekOffset: 0,
      constraints: null,
      forceSixRows: null,
      selectedDate: null,
      doneRendering: null,
      daysOfTheWeek: null,
      multiDayEvents: null,
      startWithMonth: null,
      dateParameter: 'date',
      template: clndrTemplate,
      showAdjacentMonths: true,
      trackSelectedDate: false,
      formatWeekdayHeader: null,
      adjacentDaysChangeMonth: false,
      ignoreInactiveDaysInSelection: null,
      lengthOfTime: {
        days: null,
        interval: 1,
        months: null
      },
      clickEvents: {
        click: null,
        today: null,
        nextYear: null,
        nextMonth: null,
        nextInterval: null,
        previousYear: null,
        onYearChange: null,
        previousMonth: null,
        onMonthChange: null,
        previousInterval: null,
        onIntervalChange: null
      },
      targets: {
        day: 'day',
        empty: 'empty',
        nextButton: 'clndr-next-button',
        todayButton: 'clndr-today-button',
        previousButton: 'clndr-previous-button',
        nextYearButton: 'clndr-next-year-button',
        previousYearButton: 'clndr-previous-year-button'
      },
      classes: {
        past: 'past',
        today: 'today',
        event: 'event',
        inactive: 'inactive',
        selected: 'selected',
        lastMonth: 'last-month',
        nextMonth: 'next-month',
        adjacentMonth: 'adjacent-month'
      }
    };
  
    /**
     * The actual plugin constructor.
     * Parses the events and lengthOfTime options to build a calendar of day
     * objects containing event information from the events array.
     */
    function Clndr (element, options) {
      var dayDiff;
      var constraintEnd;
      var constraintStart;
  
      this.element = element;
  
      // Merge the default options with user-provided options
      this.options = $.extend(true, {}, defaults, options);
  
      // Check if moment was passed in as a dependency
      if (this.options.moment) {
        moment = this.options.moment;
      }
  
      // Validate any correct options
      this.validateOptions();
  
      // Boolean values used to log if any contraints are met
      this.constraints = {
        next: true,
        today: true,
        previous: true,
        nextYear: true,
        previousYear: true
      };
  
      // If there are events, we should run them through our
      // addMomentObjectToEvents function which will add a date object that
      // we can use to make life easier. This is only necessarywhen events
      // are provided on instantiation, since our setEvents function uses
      // addMomentObjectToEvents.
      if (this.options.events.length) {
        if (this.options.multiDayEvents) {
          this.options.events =
            this.addMultiDayMomentObjectsToEvents(this.options.events);
        } else {
          this.options.events =
            this.addMomentObjectToEvents(this.options.events);
        }
      }
  
      // This used to be a place where we'd figure out the current month,
      // but since we want to open up support for arbitrary lengths of time
      // we're going to store the current range in addition to the current
      // month.
      if (this.options.lengthOfTime.months || this.options.lengthOfTime.days) {
        // We want to establish intervalStart and intervalEnd, which will
        // keep track of our boundaries. Let's look at the possibilities...
        if (this.options.lengthOfTime.months) {
          // Gonna go right ahead and annihilate any chance for bugs here
          this.options.lengthOfTime.days = null;
  
          // The length is specified in months. Is there a start date?
          if (this.options.lengthOfTime.startDate) {
            this.intervalStart =
              moment(this.options.lengthOfTime.startDate).startOf('month');
          } else if (this.options.startWithMonth) {
            this.intervalStart =
              moment(this.options.startWithMonth).startOf('month');
          } else {
            this.intervalStart = moment().startOf('month');
          }
  
          // Subtract a day so that we are at the end of the interval. We
          // always want intervalEnd to be inclusive.
          this.intervalEnd = moment(this.intervalStart)
            .add(this.options.lengthOfTime.months, 'months')
            .subtract(1, 'days');
          this.month = this.intervalStart.clone();
        } else if (this.options.lengthOfTime.days) {
          // The length is specified in days. Start date?
          if (this.options.lengthOfTime.startDate) {
            this.intervalStart =
              moment(this.options.lengthOfTime.startDate).startOf('day');
          } else {
            this.intervalStart = moment()
              .weekday(this.options.weekOffset)
              .startOf('day');
          }
  
          this.intervalEnd = moment(this.intervalStart)
            .add(this.options.lengthOfTime.days - 1, 'days')
            .endOf('day');
          this.month = this.intervalStart.clone();
        }
      // No length of time specified so we're going to default into using the
      // current month as the time period.
      } else {
        this.month = moment().startOf('month');
        this.intervalStart = moment(this.month);
        this.intervalEnd = moment(this.month).endOf('month');
      }
  
      if (this.options.startWithMonth) {
        this.month = moment(this.options.startWithMonth).startOf('month');
        this.intervalStart = moment(this.month);
        this.intervalEnd = this.options.lengthOfTime.days
          ? moment(this.month)
            .add(this.options.lengthOfTime.days - 1, 'days')
            .endOf('day')
          : moment(this.month).endOf('month');
      }
  
      // If we've got constraints set, make sure the interval is within them.
      if (this.options.constraints) {
        // First check if the startDate exists & is later than now.
        if (this.options.constraints.startDate) {
          constraintStart = moment(this.options.constraints.startDate);
  
          // We need to handle the constraints differently for weekly
          // calendars vs. monthly calendars.
          if (this.options.lengthOfTime.days) {
            if (this.intervalStart.isBefore(constraintStart, 'week')) {
              this.intervalStart = constraintStart.startOf('week');
            }
  
            // If the new interval period is less than the desired length
            // of time, or before the starting interval, then correct it.
            dayDiff = this.intervalStart.diff(this.intervalEnd, 'days');
  
            if (dayDiff < this.options.lengthOfTime.days ||
                this.intervalEnd.isBefore(this.intervalStart)
            ) {
              this.intervalEnd = moment(this.intervalStart)
                .add(this.options.lengthOfTime.days - 1, 'days')
                .endOf('day');
              this.month = this.intervalStart.clone();
            }
          } else {
            if (this.intervalStart.isBefore(constraintStart, 'month')) {
              // Try to preserve the date by moving only the month.
              this.intervalStart
                .set('month', constraintStart.month())
                .set('year', constraintStart.year());
              this.month
                .set('month', constraintStart.month())
                .set('year', constraintStart.year());
            }
  
            // Check if the ending interval is earlier than now.
            if (this.intervalEnd.isBefore(constraintStart, 'month')) {
              this.intervalEnd
                .set('month', constraintStart.month())
                .set('year', constraintStart.year());
            }
          }
        }
  
        // Make sure the intervalEnd is before the endDate.
        if (this.options.constraints.endDate) {
          constraintEnd = moment(this.options.constraints.endDate);
  
          // We need to handle the constraints differently for weekly
          // calendars vs. monthly calendars.
          if (this.options.lengthOfTime.days) {
            // The starting interval is after our ending constraint.
            if (this.intervalStart.isAfter(constraintEnd, 'week')) {
              this.intervalStart = moment(constraintEnd)
                .endOf('week')
                .subtract(this.options.lengthOfTime.days - 1, 'days')
                .startOf('day');
              this.intervalEnd = moment(constraintEnd)
                .endOf('week');
              this.month = this.intervalStart.clone();
            }
          } else {
            if (this.intervalEnd.isAfter(constraintEnd, 'month')) {
              this.intervalEnd
                .set('month', constraintEnd.month())
                .set('year', constraintEnd.year());
              this.month
                .set('month', constraintEnd.month())
                .set('year', constraintEnd.year());
            }
  
            // Check if the starting interval is later than the ending.
            if (this.intervalStart.isAfter(constraintEnd, 'month')) {
              this.intervalStart
                .set('month', constraintEnd.month())
                .set('year', constraintEnd.year());
            }
          }
        }
      }
  
      this._defaults = defaults;
      this._name = pluginName;
  
      // Some first-time initialization -> day of the week offset, template
      // compiling, making and storing some elements we'll need later, and
      // event handling for the controller.
      this.init();
    }
  
    /**
     * Calendar initialization.
     * Sets up the days of the week, the rendering function, binds all of the
     * events to the rendered calendar, and then stores the node locally.
     */
    Clndr.prototype.init = function () {
      var i;
      var formatWeekday;
  
      // Create the days of the week using moment's current language setting
      this.daysOfTheWeek = this.options.daysOfTheWeek || [];
  
      // User can supply an optional function to format the weekday header
      formatWeekday = this.options.formatWeekdayHeader || formatWeekday;
  
      if (!this.options.daysOfTheWeek) {
        this.daysOfTheWeek = [];
  
        formatWeekday = this.options.formatWeekdayHeader || function (day) {
          return day.format('dd').charAt(0);
        };
  
        for (i = 0; i < 7; i++) {
          this.daysOfTheWeek.push(formatWeekday(moment().weekday(i)));
        }
      }
  
      // Shuffle the week if there's an offset
      if (this.options.weekOffset) {
        this.daysOfTheWeek = this.shiftWeekdayLabels(this.options.weekOffset);
      }
  
      // Quick and dirty test to make sure rendering is possible.
      if (!$.isFunction(this.options.render)) {
        this.options.render = null;
  
        if (typeof _ === 'undefined') {
          throw new Error(
            'Underscore was not found. Please include underscore.js ' +
            'OR provide a custom render function.');
        } else {
          // We're just going ahead and using underscore here if no
          // render method has been supplied.
          this.compiledClndrTemplate = _.template(this.options.template);
        }
      }
  
      // Create the parent element that will hold the plugin and save it
      // for later
      $(this.element).html("<div class='clndr'></div>");
      this.calendarContainer = $('.clndr', this.element);
  
      // Attach event handlers for clicks on buttons/cells
      this.bindEvents();
  
      // Do a normal render of the calendar template
      this.render();
  
      // If a ready callback has been provided, call it.
      if (this.options.ready) {
        this.options.ready.apply(this, []);
      }
    };
  
    Clndr.prototype.validateOptions = function () {
      // Fix the week offset. It must be between 0 (Sunday) and 6 (Saturday)
      if (this.options.weekOffset > 6 || this.options.weekOffset < 0) {
        console.warn(
          'clndr.js: An invalid offset ' + this.options.weekOffset +
          ' was provided (must be 0 - 6); using 0 instead.');
        this.options.weekOffset = 0;
      }
    };
  
    Clndr.prototype.shiftWeekdayLabels = function (offset) {
      var i;
      var days = this.daysOfTheWeek;
  
      for (i = 0; i < offset; i++) {
        days.push(days.shift());
      }
  
      return days;
    };
  
    /**
     * This is where the magic happens. Given a starting date and ending date,
     * an array of calendarDay objects is constructed that contains appropriate
     * events and classes depending on the circumstance.
     */
    Clndr.prototype.createDaysObject = function (startDate, endDate) {
      var i;
      var day;
      var diff;
      var dateIterator;
      // This array will hold numbers for the entire grid (even the blank spaces)
      var daysArray = [];
      var endOfNextMonth;
      var endOfLastMonth;
      var startOfNextMonth;
      var startOfLastMonth;
      var date = startDate.clone();
      var lengthOfInterval = endDate.diff(startDate, 'days');
  
      // This is a helper object so that days can resolve their classes
      // correctly. Don't use it for anything please.
      this._currentIntervalStart = startDate.clone();
  
      // Filter the events list (if it exists) to events that are happening
      // last month, this month and next month (within the current grid view).
      this.eventsLastMonth = [];
      this.eventsNextMonth = [];
      this.eventsThisInterval = [];
  
      // Event parsing
      if (this.options.events.length) {
        // Here are the only two cases where we don't get an event in our
        // interval:
        //   startDate | endDate | e.start   | e.end
        //   e.start   | e.end   | startDate | endDate
        this.eventsThisInterval = $(this.options.events).filter(
          function () {
            var afterEnd = this._clndrStartDateObject.isAfter(endDate);
            var beforeStart = this._clndrEndDateObject.isBefore(startDate);
  
            if (beforeStart || afterEnd) {
              return false;
            }
            return true;
          }).toArray();
  
        if (this.options.showAdjacentMonths) {
          startOfLastMonth = startDate.clone()
            .subtract(1, 'months')
            .startOf('month');
          endOfLastMonth = startOfLastMonth.clone().endOf('month');
          startOfNextMonth = endDate.clone()
            .add(1, 'months')
            .startOf('month');
          endOfNextMonth = startOfNextMonth.clone().endOf('month');
  
          this.eventsLastMonth = $(this.options.events).filter(
            function () {
              var beforeStart = this._clndrEndDateObject
                .isBefore(startOfLastMonth);
              var afterEnd = this._clndrStartDateObject
                .isAfter(endOfLastMonth);
  
              return !(beforeStart || afterEnd);
            }).toArray();
  
          this.eventsNextMonth = $(this.options.events).filter(
            function () {
              var beforeStart = this._clndrEndDateObject
                .isBefore(startOfNextMonth);
              var afterEnd = this._clndrStartDateObject
                .isAfter(endOfNextMonth);
  
              return !(beforeStart || afterEnd);
            }).toArray();
        }
      }
  
      // If diff is greater than 0, we'll have to fill in last days of the
      // previous month to account for the empty boxes in the grid. We also
      // need to take into account the weekOffset parameter. None of this
      // needs to happen if the interval is being specified in days rather
      // than months.
      if (!this.options.lengthOfTime.days) {
        diff = date.weekday() - this.options.weekOffset;
  
        if (diff < 0) {
          diff += 7;
        }
  
        if (this.options.showAdjacentMonths) {
          for (i = 1; i <= diff; i++) {
            day = moment([
              startDate.year(),
              startDate.month(),
              i
            ]).subtract(diff, 'days');
            daysArray.push(
              this.createDayObject(
                day,
                this.eventsLastMonth
              ));
          }
        } else {
          for (i = 0; i < diff; i++) {
            daysArray.push(
              this.calendarDay({
                classes: this.options.targets.empty +
                  ' ' + this.options.classes.lastMonth
              }));
          }
        }
      }
  
      // Now we push all of the days in the interval
      dateIterator = startDate.clone();
  
      while (dateIterator.isBefore(endDate) || dateIterator.isSame(endDate, 'day')) {
        daysArray.push(
          this.createDayObject(
            dateIterator.clone(),
            this.eventsThisInterval
          ));
        dateIterator.add(1, 'days');
      }
  
      // ...and if there are any trailing blank boxes, fill those in with the
      // next month first days. Again, we can ignore this if the interval is
      // specified in days.
      if (!this.options.lengthOfTime.days) {
        while (daysArray.length % 7 !== 0) {
          if (this.options.showAdjacentMonths) {
            daysArray.push(
              this.createDayObject(
                dateIterator.clone(),
                this.eventsNextMonth
              ));
          } else {
            daysArray.push(
              this.calendarDay({
                classes: this.options.targets.empty + ' ' +
                  this.options.classes.nextMonth
              }));
          }
          dateIterator.add(1, 'days');
        }
      }
  
      // If we want to force six rows of calendar, now's our Last Chance to
      // add another row. If the 42 seems explicit it's because we're
      // creating a 7-row grid and 6 rows of 7 is always 42!
      if (this.options.forceSixRows && daysArray.length !== 42) {
        while (daysArray.length < 42) {
          if (this.options.showAdjacentMonths) {
            daysArray.push(
              this.createDayObject(
                dateIterator.clone(),
                this.eventsNextMonth
              ));
            dateIterator.add(1, 'days');
          } else {
            daysArray.push(this.calendarDay({
              classes: this.options.targets.empty + ' ' +
                this.options.classes.nextMonth
            }));
          }
        }
      }
  
      return daysArray;
    };
  
    Clndr.prototype.createDayObject = function (day, monthEvents) {
      var end;
      var j = 0;
      var start;
      var dayEnd;
      var endMoment;
      var startMoment;
      var selectedMoment;
      var now = moment();
      var eventsToday = [];
      var extraClasses = '';
      var properties = {
        isToday: false,
        isInactive: false,
        isAdjacentMonth: false
      };
  
      // Validate moment date
      if (!day.isValid() && day.hasOwnProperty('_d') && day._d !== undefined) {
        day = moment(day._d);
      }
  
      // Set to the end of the day for comparisons
      dayEnd = day.clone().endOf('day');
  
      for (j; j < monthEvents.length; j++) {
        // Keep in mind that the events here already passed the month/year
        // test. Now all we have to compare is the moment.date(), which
        // returns the day of the month.
        start = monthEvents[j]._clndrStartDateObject;
        end = monthEvents[j]._clndrEndDateObject;
  
        // If today is the same day as start or is after the start, and
        // if today is the same day as the end or before the end ...
        // woohoo semantics!
        if (start <= dayEnd && day <= end) {
          eventsToday.push(monthEvents[j]);
        }
      }
  
      if (now.format('YYYY-MM-DD') === day.format('YYYY-MM-DD')) {
        extraClasses += (' ' + this.options.classes.today);
        properties.isToday = true;
      }
  
      if (day.isBefore(now, 'day')) {
        extraClasses += (' ' + this.options.classes.past);
      }
  
      if (eventsToday.length) {
        extraClasses += (' ' + this.options.classes.event);
      }
  
      if (!this.options.lengthOfTime.days) {
        if (this._currentIntervalStart.month() > day.month()) {
          extraClasses += (' ' + this.options.classes.adjacentMonth);
          properties.isAdjacentMonth = true;
  
          this._currentIntervalStart.year() === day.year()
            ? extraClasses += (' ' + this.options.classes.lastMonth)
            : extraClasses += (' ' + this.options.classes.nextMonth);
        } else if (this._currentIntervalStart.month() < day.month()) {
          extraClasses += (' ' + this.options.classes.adjacentMonth);
          properties.isAdjacentMonth = true;
  
          this._currentIntervalStart.year() === day.year()
            ? extraClasses += (' ' + this.options.classes.nextMonth)
            : extraClasses += (' ' + this.options.classes.lastMonth);
        }
      }
  
      // If there are constraints, we need to add the inactive class to the
      // days outside of them
      if (this.options.constraints) {
        endMoment = moment(this.options.constraints.endDate);
        startMoment = moment(this.options.constraints.startDate);
  
        if (this.options.constraints.startDate && day.isBefore(startMoment)) {
          extraClasses += (' ' + this.options.classes.inactive);
          properties.isInactive = true;
        }
  
        if (this.options.constraints.endDate && day.isAfter(endMoment)) {
          extraClasses += (' ' + this.options.classes.inactive);
          properties.isInactive = true;
        }
      }
  
      // Validate moment date
      if (!day.isValid() && day.hasOwnProperty('_d') && day._d !== undefined) {
        day = moment(day._d);
      }
  
      // Check whether the day is "selected"
      selectedMoment = moment(this.options.selectedDate);
  
      if (this.options.selectedDate && day.isSame(selectedMoment, 'day')) {
        extraClasses += (' ' + this.options.classes.selected);
      }
  
      // We're moving away from using IDs in favor of classes, since when
      // using multiple calendars on a page we are technically violating the
      // uniqueness of IDs.
      extraClasses += ' calendar-day-' + day.format('YYYY-MM-DD');
      // Day of week
      extraClasses += ' calendar-dow-' + day.weekday();
  
      return this.calendarDay({
        date: day,
        day: day.date(),
        events: eventsToday,
        properties: properties,
        classes: this.options.targets.day + extraClasses
      });
    };
  
    /**
     * Renders the calendar.
     *
     * Get rid of the previous set of calendar parts. This should handle garbage
     * collection according to jQuery's docs:
     *   http://api.jquery.com/empty/
     * To avoid memory leaks, jQuery removes other constructs such as
     * data and event handlers from the child elements before removing
     * the elements themselves.
     */
    Clndr.prototype.render = function () {
      var i;
      var days;
      var months;
      var target;
      var data = {};
      var end = null;
      var start = null;
      var numberOfRows;
      var eventsThisInterval;
      var currentIntervalEnd;
      var currentIntervalStart;
      var oneYearFromEnd = this.intervalEnd.clone().add(1, 'years');
      var oneYearAgo = this.intervalStart.clone().subtract(1, 'years');
  
      this.calendarContainer.empty();
  
      if (this.options.lengthOfTime.days) {
        days = this.createDaysObject(
          this.intervalStart.clone(),
          this.intervalEnd.clone());
        data = {
          days: days,
          months: [],
          year: null,
          month: null,
          eventsLastMonth: [],
          eventsNextMonth: [],
          eventsThisMonth: [],
          extras: this.options.extras,
          daysOfTheWeek: this.daysOfTheWeek,
          intervalEnd: this.intervalEnd.clone(),
          numberOfRows: Math.ceil(days.length / 7),
          intervalStart: this.intervalStart.clone(),
          eventsThisInterval: this.eventsThisInterval
        };
      } else if (this.options.lengthOfTime.months) {
        months = [];
        numberOfRows = 0;
        eventsThisInterval = [];
  
        for (i = 0; i < this.options.lengthOfTime.months; i++) {
          currentIntervalStart = this.intervalStart
            .clone()
            .add(i, 'months');
          currentIntervalEnd = currentIntervalStart
            .clone()
            .endOf('month');
          days = this.createDaysObject(currentIntervalStart, currentIntervalEnd);
          // Save events processed for each month into a master array of
          // events for this interval
          eventsThisInterval.push(this.eventsThisInterval);
          months.push({
            days: days,
            month: currentIntervalStart
          });
        }
  
              // Get the total number of rows across all months
        for (i = 0; i < months.length; i++) {
          numberOfRows += Math.ceil(months[i].days.length / 7);
        }
  
        data = {
          days: [],
          year: null,
          month: null,
          months: months,
          eventsThisMonth: [],
          numberOfRows: numberOfRows,
          extras: this.options.extras,
          intervalEnd: this.intervalEnd,
          intervalStart: this.intervalStart,
          daysOfTheWeek: this.daysOfTheWeek,
          eventsLastMonth: this.eventsLastMonth,
          eventsNextMonth: this.eventsNextMonth,
          eventsThisInterval: eventsThisInterval
        };
      } else {
        // Get an array of days and blank spaces
        days = this.createDaysObject(
          this.month.clone().startOf('month'),
          this.month.clone().endOf('month')
        );
  
        data = {
          days: days,
          months: [],
          intervalEnd: null,
          intervalStart: null,
          year: this.month.year(),
          eventsThisInterval: null,
          extras: this.options.extras,
          month: this.month.format('MMMM'),
          daysOfTheWeek: this.daysOfTheWeek,
          eventsLastMonth: this.eventsLastMonth,
          eventsNextMonth: this.eventsNextMonth,
          numberOfRows: Math.ceil(days.length / 7),
          eventsThisMonth: this.eventsThisInterval
        };
      }
  
      // Render the calendar with the data above & bind events to its elements
      if (this.options.render) {
        this.calendarContainer.html(this.options.render.apply(this, [data]));
      } else {
        this.calendarContainer.html(this.compiledClndrTemplate(data));
      }
  
      // If there are constraints, we need to add the 'inactive' class to
      // the controls.
      if (this.options.constraints) {
        // In the interest of clarity we're just going to remove all
        // inactive classes and re-apply them each render.
        for (target in this.options.targets) {
          if (target !== 'day') {
            this.element
              .find('.' + this.options.targets[target])
              .toggleClass(this.options.classes.inactive, false);
          }
        }
  
        // Just like the classes we'll set this internal state to true and
        // handle the disabling below.
        for (i in this.constraints) {
          this.constraints[i] = true;
        }
  
        if (this.options.constraints.startDate) {
          start = moment(this.options.constraints.startDate);
        }
  
        if (this.options.constraints.endDate) {
          end = moment(this.options.constraints.endDate);
        }
  
        // Deal with the month controls first. Do we have room to go back?
        if (start &&
            (start.isAfter(this.intervalStart) ||
              start.isSame(this.intervalStart, 'day'))
        ) {
          this.element.find('.' + this.options.targets.previousButton)
            .toggleClass(this.options.classes.inactive, true);
          this.constraints.previous = !this.constraints.previous;
        }
  
        // Do we have room to go forward?
        if (end &&
            (end.isBefore(this.intervalEnd) ||
              end.isSame(this.intervalEnd, 'day'))
        ) {
          this.element.find('.' + this.options.targets.nextButton)
            .toggleClass(this.options.classes.inactive, true);
          this.constraints.next = !this.constraints.next;
        }
  
        // What's last year looking like?
        if (start && start.isAfter(oneYearAgo)) {
          this.element
            .find('.' + this.options.targets.previousYearButton)
            .toggleClass(this.options.classes.inactive, true);
          this.constraints.previousYear = !this.constraints.previousYear;
        }
  
        // How about next year?
        if (end && end.isBefore(oneYearFromEnd)) {
          this.element
            .find('.' + this.options.targets.nextYearButton)
            .toggleClass(this.options.classes.inactive, true);
          this.constraints.nextYear = !this.constraints.nextYear;
        }
  
        // Today? We could put this in init(), but we want to support the
        // user changing the constraints on a living instance.
        if ((start && start.isAfter(moment(), 'month')) ||
            (end && end.isBefore(moment(), 'month'))
        ) {
          this.element.find('.' + this.options.targets.today)
            .toggleClass(this.options.classes.inactive, true);
          this.constraints.today = !this.constraints.today;
        }
      }
  
      if (this.options.doneRendering) {
        this.options.doneRendering.apply(this, []);
      }
    };
  
    Clndr.prototype.bindEvents = function () {
      var data = {};
      var self = this;
      var $container = $(this.element);
      var targets = this.options.targets;
      var classes = self.options.classes;
      var eventType = this.options.useTouchEvents === true
        ? 'touchstart'
        : 'click';
      var eventName = eventType + '.clndr';
  
      // Make sure we don't already have events
      $container
        .off(eventName, '.' + targets.day)
        .off(eventName, '.' + targets.empty)
        .off(eventName, '.' + targets.nextButton)
        .off(eventName, '.' + targets.todayButton)
        .off(eventName, '.' + targets.previousButton)
        .off(eventName, '.' + targets.nextYearButton)
        .off(eventName, '.' + targets.previousYearButton);
  
      // Target the day elements and give them click events
      $container.on(eventName, '.' + targets.day, function (event) {
        var target;
        var $currentTarget = $(event.currentTarget);
  
        // If adjacentDaysChangeMonth is on, we need to change the
        // month here. Forward and Back trigger render() to be called.
        // This is a callback because it can be triggered in two places.
        var handleAdjacentDay = function () {
          if (self.options.adjacentDaysChangeMonth) {
            if ($currentTarget.is('.' + classes.lastMonth)) {
              self.backActionWithContext(self);
              return true;
            } else if ($currentTarget.is('.' + classes.nextMonth)) {
              self.forwardActionWithContext(self);
              return true;
            }
          }
        };
  
        // If setting is enabled, we want to store the selected date
        // as a string. When render() is called, the selected date will
        // get the additional classes added. If there is no re-render,
        // then just add the classes manually.
        if (self.options.trackSelectedDate &&
            !(self.options.ignoreInactiveDaysInSelection &&
              $currentTarget.hasClass(classes.inactive))
        ) {
          // If there was no re-render, manually update classes
          if (handleAdjacentDay() !== true) {
            // Remember new selected date
            self.options.selectedDate =
              self.getTargetDateString(event.currentTarget);
            $container.find('.' + classes.selected)
              .removeClass(classes.selected);
            $currentTarget.addClass(classes.selected);
          }
        } else {
          handleAdjacentDay();
        }
  
        // Trigger click events after any selected date updates
        if (self.options.clickEvents.click) {
          target = self.buildTargetObject(event.currentTarget, true);
          self.options.clickEvents.click.apply(self, [target]);
        }
      });
  
      // Target the empty calendar boxes as well
      $container.on(eventName, '.' + targets.empty, function (event) {
        var target;
        var $eventTarget = $(event.currentTarget);
  
        if (self.options.clickEvents.click) {
          target = self.buildTargetObject(event.currentTarget, false);
          self.options.clickEvents.click.apply(self, [target]);
        }
  
        if (self.options.adjacentDaysChangeMonth) {
          if ($eventTarget.is('.' + classes.lastMonth)) {
            self.backActionWithContext(self);
          } else if ($eventTarget.is('.' + classes.nextMonth)) {
            self.forwardActionWithContext(self);
          }
        }
      });
  
      // Bind the previous, next and today buttons. We pass the current
      // context along with the event so that it can update this instance.
      data = {
        context: this
      };
  
      $container
        .on(eventName, '.' + targets.todayButton, data, this.todayAction)
        .on(eventName, '.' + targets.nextButton, data, this.forwardAction)
        .on(eventName, '.' + targets.previousButton, data, this.backAction)
        .on(eventName, '.' + targets.nextYearButton, data, this.nextYearAction)
        .on(eventName, '.' + targets.previousYearButton, data, this.previousYearAction);
    };
  
    /**
     * If the user provided a click callback we'd like to give them something
     * nice to work with. buildTargetObject takes the DOM element that was
     * clicked and returns an object with the DOM element, events, and the date
     * (if the latter two exist). Currently it is based on the id, however it'd
     * be nice to use a data- attribute in the future.
     */
    Clndr.prototype.buildTargetObject = function (currentTarget, targetWasDay) {
      // This is our default target object, assuming we hit an empty day
      // with no events.
      var target = {
        date: null,
        events: [],
        element: currentTarget
      };
      var filterFn;
      var dateString;
      var targetEndDate;
  
      // Did we click on a day or just an empty box?
      if (targetWasDay) {
        dateString = this.getTargetDateString(currentTarget);
        target.date = dateString
          ? moment(dateString)
          : null;
  
        // Do we have events?
        if (this.options.events) {
          // Are any of the events happening today?
          if (this.options.multiDayEvents) {
            targetEndDate = target.date.clone().endOf('day');
            filterFn = function () {
              return this._clndrStartDateObject <= targetEndDate &&
                target.date <= this._clndrEndDateObject;
            };
          } else {
            filterFn = function () {
              return dateString === this._clndrStartDateObject.format('YYYY-MM-DD');
            };
          }
  
          // Filter the dates down to the ones that match.
          target.events = $.makeArray($(this.options.events).filter(filterFn));
        }
      }
  
      return target;
    };
  
    /**
     * Get moment date object of the date associated with the given target.
     * This method is meant to be called on ".day" elements.
     */
    Clndr.prototype.getTargetDateString = function (target) {
      // Our identifier is in the list of classNames. Find it!
      var index = target.className.indexOf('calendar-day-');
  
      if (index !== -1) {
        // Our unique identifier is always 23 characters long.
        // If this feels a little wonky, that's probably because it is.
        // Open to suggestions on how to improve this guy.
        return target.className.substring(index + 13, index + 23);
      }
  
      return null;
    };
  
    /**
     * Triggers any applicable events given a change in the calendar's start
     * and end dates. ctx contains the current (changed) start and end date,
     * orig contains the original start and end dates.
     */
    Clndr.prototype.triggerEvents = function (ctx, orig) {
      var nextYear;
      var prevYear;
      var nextMonth;
      var prevMonth;
      var yearChanged;
      var monthChanged;
      var nextInterval;
      var prevInterval;
      var intervalChanged;
      var monthArg = [moment(ctx.month)];
      var timeOpt = ctx.options.lengthOfTime;
      var eventsOpt = ctx.options.clickEvents;
      var newInt = {
        end: ctx.intervalEnd,
        start: ctx.intervalStart
      };
      var intervalArg = [
        moment(ctx.intervalStart),
        moment(ctx.intervalEnd)
      ];
  
      // We want to determine if any of the change conditions have been
      // hit and then trigger our events based off that.
      nextMonth = newInt.start.isAfter(orig.start) &&
        (Math.abs(newInt.start.month() - orig.start.month()) === 1 ||
          (orig.start.month() === 11 && newInt.start.month() === 0));
      prevMonth = newInt.start.isBefore(orig.start) &&
        (Math.abs(orig.start.month() - newInt.start.month()) === 1 ||
          (orig.start.month() === 0 && newInt.start.month() === 11));
      monthChanged = newInt.start.month() !== orig.start.month() ||
          newInt.start.year() !== orig.start.year();
      nextYear = newInt.start.year() - orig.start.year() === 1 ||
          newInt.end.year() - orig.end.year() === 1;
      prevYear = orig.start.year() - newInt.start.year() === 1 ||
          orig.end.year() - newInt.end.year() === 1;
      yearChanged = newInt.start.year() !== orig.start.year();
  
      // Only configs with a time period will get the interval change event
      if (timeOpt.days || timeOpt.months) {
        nextInterval = newInt.start.isAfter(orig.start);
        prevInterval = newInt.start.isBefore(orig.start);
        intervalChanged = nextInterval || prevInterval;
  
        if (nextInterval && eventsOpt.nextInterval) {
          eventsOpt.nextInterval.apply(ctx, intervalArg);
        }
  
        if (prevInterval && eventsOpt.previousInterval) {
          eventsOpt.previousInterval.apply(ctx, intervalArg);
        }
  
        if (intervalChanged && eventsOpt.onIntervalChange) {
          eventsOpt.onIntervalChange.apply(ctx, intervalArg);
        }
      } else {
        // @V2-todo see https://github.com/kylestetz/CLNDR/issues/225
        if (nextMonth && eventsOpt.nextMonth) {
          eventsOpt.nextMonth.apply(ctx, monthArg);
        }
  
        if (prevMonth && eventsOpt.previousMonth) {
          eventsOpt.previousMonth.apply(ctx, monthArg);
        }
  
        if (monthChanged && eventsOpt.onMonthChange) {
          eventsOpt.onMonthChange.apply(ctx, monthArg);
        }
  
        if (nextYear && eventsOpt.nextYear) {
          eventsOpt.nextYear.apply(ctx, monthArg);
        }
  
        if (prevYear && eventsOpt.previousYear) {
          eventsOpt.previousYear.apply(ctx, monthArg);
        }
  
        if (yearChanged && eventsOpt.onYearChange) {
          eventsOpt.onYearChange.apply(ctx, monthArg);
        }
      }
    };
  
    /**
     * Main action to go backward one period. Other methods call these, like
     * backAction which proxies jQuery events, and backActionWithContext which
     * is an internal method that this library uses.
     */
    Clndr.prototype.back = function (options /*, ctx */) {
      var ctx = arguments[ 1 ] || this;
      var timeOpt = ctx.options.lengthOfTime;
      var defaults = {
        withCallbacks: false
      };
      var orig = {
        end: ctx.intervalEnd.clone(),
        start: ctx.intervalStart.clone()
      };
  
      // Extend any options
      options = $.extend(true, {}, defaults, options);
  
      // Before we do anything, check if any constraints are limiting this
      if (!ctx.constraints.previous) {
        return ctx;
      }
  
      if (timeOpt.days) {
        // Shift the interval in days
        ctx.intervalStart
          .subtract(timeOpt.interval, 'days')
          .startOf('day');
        ctx.intervalEnd = ctx.intervalStart.clone()
          .add(timeOpt.days - 1, 'days')
          .endOf('day');
        // @V2-todo Useless, but consistent with API
        ctx.month = ctx.intervalStart.clone();
      } else {
        // Shift the interval by a month (or several months)
        ctx.intervalStart
          .subtract(timeOpt.interval, 'months')
          .startOf('month');
        ctx.intervalEnd = ctx.intervalStart.clone()
          .add(timeOpt.months || timeOpt.interval, 'months')
          .subtract(1, 'days')
          .endOf('month');
        ctx.month = ctx.intervalStart.clone();
      }
  
      ctx.render();
  
      if (options.withCallbacks) {
        ctx.triggerEvents(ctx, orig);
      }
  
      return ctx;
    };
  
    Clndr.prototype.backAction = function (event) {
      var ctx = event.data.context;
  
      ctx.backActionWithContext(ctx);
    };
  
    Clndr.prototype.backActionWithContext = function (ctx) {
      ctx.back({
        withCallbacks: true
      }, ctx);
    };
  
    Clndr.prototype.previous = function (options) {
      // Alias
      return this.back(options);
    };
  
    /**
     * Main action to go forward one period. Other methods call these, like
     * forwardAction which proxies jQuery events, and backActionWithContext
     * which is an internal method that this library uses.
     */
    Clndr.prototype.forward = function (options /*, ctx */) {
      var ctx = arguments[1] || this;
      var timeOpt = ctx.options.lengthOfTime;
      var defaults = {
        withCallbacks: false
      };
      var orig = {
        end: ctx.intervalEnd.clone(),
        start: ctx.intervalStart.clone()
      };
  
      // Extend any options
      options = $.extend(true, {}, defaults, options);
  
      // Before we do anything, check if any constraints are limiting this
      if (!ctx.constraints.next) {
        return ctx;
      }
  
      if (ctx.options.lengthOfTime.days) {
        // Shift the interval in days
        ctx.intervalStart
          .add(timeOpt.interval, 'days')
          .startOf('day');
        ctx.intervalEnd = ctx.intervalStart.clone()
          .add(timeOpt.days - 1, 'days')
          .endOf('day');
        // @V2-todo Useless, but consistent with API
        ctx.month = ctx.intervalStart.clone();
      } else {
        // Shift the interval by a month (or several months)
        ctx.intervalStart
          .add(timeOpt.interval, 'months')
          .startOf('month');
        ctx.intervalEnd = ctx.intervalStart.clone()
          .add(timeOpt.months || timeOpt.interval, 'months')
          .subtract(1, 'days')
          .endOf('month');
        ctx.month = ctx.intervalStart.clone();
      }
  
      ctx.render();
  
      if (options.withCallbacks) {
        ctx.triggerEvents(ctx, orig);
      }
  
      return ctx;
    };
  
    Clndr.prototype.forwardAction = function (event) {
      var ctx = event.data.context;
  
      ctx.forwardActionWithContext(ctx);
    };
  
    Clndr.prototype.forwardActionWithContext = function (ctx) {
      ctx.forward({
        withCallbacks: true
      }, ctx);
    };
  
    Clndr.prototype.next = function (options) {
      // Alias
      return this.forward(options);
    };
  
    /**
     * Main action to go back one year.
     */
    Clndr.prototype.previousYear = function (options /*, ctx */) {
      var ctx = arguments[1] || this;
      var defaults = {
        withCallbacks: false
      };
      var orig = {
        end: ctx.intervalEnd.clone(),
        start: ctx.intervalStart.clone()
      };
  
      // Extend any options
      options = $.extend(true, {}, defaults, options);
  
      // Before we do anything, check if any constraints are limiting this
      if (!ctx.constraints.previousYear) {
        return ctx;
      }
  
      ctx.month.subtract(1, 'year');
      ctx.intervalStart.subtract(1, 'year');
      ctx.intervalEnd.subtract(1, 'year');
      ctx.render();
  
      if (options.withCallbacks) {
        ctx.triggerEvents(ctx, orig);
      }
  
      return ctx;
    };
  
    Clndr.prototype.previousYearAction = function (event) {
      event.data.context.previousYear({
        withCallbacks: true
      }, event.data.context);
    };
  
    /**
     * Main action to go forward one year.
     */
    Clndr.prototype.nextYear = function (options /*, ctx */) {
      var ctx = arguments[1] || this;
      var defaults = {
        withCallbacks: false
      };
      var orig = {
        end: ctx.intervalEnd.clone(),
        start: ctx.intervalStart.clone()
      };
  
      // Extend any options
      options = $.extend(true, {}, defaults, options);
  
      // Before we do anything, check if any constraints are limiting this
      if (!ctx.constraints.nextYear) {
        return ctx;
      }
  
      ctx.month.add(1, 'year');
      ctx.intervalStart.add(1, 'year');
      ctx.intervalEnd.add(1, 'year');
      ctx.render();
  
      if (options.withCallbacks) {
        ctx.triggerEvents(ctx, orig);
      }
  
      return ctx;
    };
  
    Clndr.prototype.nextYearAction = function (event) {
      event.data.context.nextYear({
        withCallbacks: true
      }, event.data.context);
    };
  
    Clndr.prototype.today = function (options /*, ctx */) {
      var ctx = arguments[1] || this;
      var timeOpt = ctx.options.lengthOfTime;
      var defaults = {
        withCallbacks: false
      };
      var orig = {
        end: ctx.intervalEnd.clone(),
        start: ctx.intervalStart.clone()
      };
  
      // Extend any options
      options = $.extend(true, {}, defaults, options);
      // @V2-todo Only used for legacy month view
      ctx.month = moment().startOf('month');
  
      if (timeOpt.days) {
        // If there was a startDate specified, we should figure out what
        // the weekday is and use that as the starting point of our
        // interval. If not, go to today.weekday(0).
        if (timeOpt.startDate) {
          ctx.intervalStart = moment()
            .weekday(timeOpt.startDate.weekday())
            .startOf('day');
        } else {
          ctx.intervalStart = moment().weekday(0).startOf('day');
        }
  
        ctx.intervalEnd = ctx.intervalStart.clone()
          .add(timeOpt.days - 1, 'days')
          .endOf('day');
      } else {
        // Set the intervalStart to this month.
        ctx.intervalStart = moment().startOf('month');
        ctx.intervalEnd = ctx.intervalStart.clone()
          .add(timeOpt.months || timeOpt.interval, 'months')
          .subtract(1, 'days')
          .endOf('month');
      }
  
      // No need to re-render if we didn't change months.
      if (!ctx.intervalStart.isSame(orig.start) ||
          !ctx.intervalEnd.isSame(orig.end)
      ) {
        ctx.render();
      }
  
      // Fire the today event handler regardless of any change
      if (options.withCallbacks) {
        if (ctx.options.clickEvents.today) {
          ctx.options.clickEvents.today.apply(ctx, [moment(ctx.month)]);
        }
  
        ctx.triggerEvents(ctx, orig);
      }
    };
  
    Clndr.prototype.todayAction = function (event) {
      event.data.context.today({
        withCallbacks: true
      }, event.data.context);
    };
  
    /**
     * Changes the month. Accepts 0-11 or a full/partial month name.
     * e.g. "Jan", "February", "Mar", etc.
     */
    Clndr.prototype.setMonth = function (newMonth, options) {
      var timeOpt = this.options.lengthOfTime;
      var orig = {
        end: this.intervalEnd.clone(),
        start: this.intervalStart.clone()
      };
  
      if (timeOpt.days || timeOpt.months) {
        console.warn(
          'clndr.js: You are using a custom date interval. ' +
          'Use Clndr.setIntervalStart(startDate) instead.');
        return this;
      }
  
      this.month.month(newMonth);
      this.intervalStart = this.month.clone().startOf('month');
      this.intervalEnd = this.intervalStart.clone().endOf('month');
      this.render();
  
      if (options && options.withCallbacks) {
        this.triggerEvents(this, orig);
      }
  
      return this;
    };
  
    Clndr.prototype.setYear = function (newYear, options) {
      var orig = {
        end: this.intervalEnd.clone(),
        start: this.intervalStart.clone()
      };
  
      this.month.year(newYear);
      this.intervalEnd.year(newYear);
      this.intervalStart.year(newYear);
      this.render();
  
      if (options && options.withCallbacks) {
        this.triggerEvents(this, orig);
      }
  
      return this;
    };
  
    /**
     * Sets the start of the time period according to newDate.
     * newDate can be a string or a moment object.
     */
    Clndr.prototype.setIntervalStart = function (newDate, options) {
      var timeOpt = this.options.lengthOfTime;
      var orig = {
        end: this.intervalEnd.clone(),
        start: this.intervalStart.clone()
      };
  
      if (!timeOpt.days && !timeOpt.months) {
        console.warn(
          'clndr.js: You are using a custom date interval. ' +
          'Use Clndr.setIntervalStart(startDate) instead.');
        return this;
      }
  
      if (timeOpt.days) {
        this.intervalStart = moment(newDate).startOf('day');
        this.intervalEnd = this.intervalStart.clone()
          .add(timeOpt.days - 1, 'days')
          .endOf('day');
      } else {
        this.intervalStart = moment(newDate).startOf('month');
        this.intervalEnd = this.intervalStart.clone()
          .add(timeOpt.months || timeOpt.interval, 'months')
          .subtract(1, 'days')
          .endOf('month');
      }
  
      this.month = this.intervalStart.clone();
      this.render();
  
      if (options && options.withCallbacks) {
        this.triggerEvents(this, orig);
      }
  
      return this;
    };
  
    /**
     * Overwrites extras in the calendar and triggers a render.
     */
    Clndr.prototype.setExtras = function (extras) {
      this.options.extras = extras;
      this.render();
  
      return this;
    };
  
    /**
     * Overwrites events in the calendar and triggers a render.
     */
    Clndr.prototype.setEvents = function (events) {
      // Go through each event and add a moment object
      if (this.options.multiDayEvents) {
        this.options.events = this.addMultiDayMomentObjectsToEvents(events);
      } else {
        this.options.events = this.addMomentObjectToEvents(events);
      }
  
      this.render();
  
      return this;
    };
  
    /**
     * Adds additional events to the calendar and triggers a render.
     */
    Clndr.prototype.addEvents = function (events /*, reRender */) {
      var reRender = arguments.length > 1
        ? arguments[1]
        : true;
  
      // Go through each event and add a moment object
      if (this.options.multiDayEvents) {
        this.options.events = $.merge(
          this.options.events,
          this.addMultiDayMomentObjectsToEvents(events));
      } else {
        this.options.events = $.merge(
          this.options.events,
          this.addMomentObjectToEvents(events));
      }
  
      if (reRender) {
        this.render();
      }
  
      return this;
    };
  
    /**
     * Passes all events through a matching function. Any that pass a truth
     * test will be removed from the calendar's events. This triggers a render.
     */
    Clndr.prototype.removeEvents = function (matchingFn) {
      var i;
  
      for (i = this.options.events.length - 1; i >= 0; i--) {
        if (matchingFn(this.options.events[i]) === true) {
          this.options.events.splice(i, 1);
        }
      }
  
      this.render();
  
      return this;
    };
  
    Clndr.prototype.addMomentObjectToEvents = function (events) {
      var i = 0;
      var self = this;
  
      for (i; i < events.length; i++) {
        // Add the date as both start and end, since it's a single-day
        // event by default
        events[i]._clndrStartDateObject =
          moment(events[i][self.options.dateParameter]);
        events[i]._clndrEndDateObject =
          moment(events[i][self.options.dateParameter]);
      }
  
      return events;
    };
  
    Clndr.prototype.addMultiDayMomentObjectsToEvents = function (events) {
      var end;
      var start;
      var i = 0;
      var self = this;
      var multiEvents = self.options.multiDayEvents;
  
      for (i; i < events.length; i++) {
        end = events[i][multiEvents.endDate];
        start = events[i][multiEvents.startDate];
  
        // If we don't find the startDate OR endDate fields, look for singleDay
        if (!end && !start) {
          events[i]._clndrEndDateObject =
            moment(events[i][multiEvents.singleDay]);
          events[i]._clndrStartDateObject =
            moment(events[i][multiEvents.singleDay]);
        } else {
          // Otherwise use startDate and endDate, or whichever one is present
          events[i]._clndrEndDateObject = moment(end || start);
          events[i]._clndrStartDateObject = moment(start || end);
        }
      }
  
      return events;
    };
  
    Clndr.prototype.calendarDay = function (options) {
      var defaults = {
        day: '',
        date: null,
        events: [],
        classes: this.options.targets.empty
      };
  
      return $.extend({}, defaults, options);
    };
  
    Clndr.prototype.destroy = function () {
      var $container = $(this.calendarContainer);
  
      $container.parent().data('plugin_clndr', null);
      $container.empty().remove();
  
      this.options = defaults;
      this.element = null;
    };
  
    $.fn.clndr = function (options) {
      var clndrInstance;
  
      if (this.length > 1) {
        throw new Error(
          'CLNDR does not support multiple elements yet. Make sure ' +
          'your clndr selector returns only one element.'
        );
      }
  
      if (!this.length) {
        throw new Error('CLNDR cannot be instantiated on an empty selector.');
      }
  
      if (!this.data('plugin_clndr')) {
        clndrInstance = new Clndr(this, options);
  
        this.data('plugin_clndr', clndrInstance);
  
        return clndrInstance;
      }
  
      return this.data('plugin_clndr');
    };
  }));